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Study on the channel of bipolar plate for PEM fuel cell (고분자 전해질 연료전지용 바이폴라 플레이트의 유로 연구)

  • Ahn Bum Jong;Ko Jae-Churl;Jo Young-Do
    • Journal of the Korean Institute of Gas
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    • v.8 no.2 s.23
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    • pp.15-27
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    • 2004
  • The purpose of this paper is to improve the performance of Polymer electrolyte fuel cell(PEMFC) by studying the channel dimension of bipolar plates using commercial CFD program 'Fluent'. Simulations are done ranging from 0.5 to 3.0mm for different size in order to find the channel size which shoves the highst hydrogen consumption. The results showed that the smaller channel width, land width, channel depth, the higher hydrogen consumption in anode. When channel width is increased, the pressure drop in channel is decreased because total channel length Is decreased, and when land width is increased, the net hydrogen consumption is decreased because hydrogen is diffused under the land width. It is also found that the influence of hydrogen consumption is larger at different channel width than it at different land width. The change of hydrogen consumption with different channel depth isn't as large as it with different channel width, but channel depth has to be small as can as it does because it has influence on the volume of bipolar plates. however the hydrogen utilization among the channel sizes more than 1.0mm which can be machined in reality is the most at channel width 1.0, land width 1.0, channel depth 0.5mm and considered as optimum channel size. The fuel cell combined with 2cm${\times}$2cm diagonal or serpentine type flow field and MEA(Membrane Electrode Assembly) is tested using 100W PEMFC test station to confirm that the channel size studied in simulation. The results showed that diagonal and serpentine flow field have similarly high OCV and current density of diagonal (low field is higher($2-40mA/m^2$) than that of serpentine flow field under 0.6 voltage, but the current density of serpentine type has higher performance($5-10mA/m^2$) than that of diagonal flow field under 0.7-0.8 voltage.

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Effects on the continuous use intention of AI-based voice assistant services: Focusing on the interaction between trust in AI and privacy concerns (인공지능 기반 음성비서 서비스의 지속이용 의도에 미치는 영향: 인공지능에 대한 신뢰와 프라이버시 염려의 상호작용을 중심으로)

  • Jang, Changki;Heo, Deokwon;Sung, WookJoon
    • Informatization Policy
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    • v.30 no.2
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    • pp.22-45
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    • 2023
  • In research on the use of AI-based voice assistant services, problems related to the user's trust and privacy protection arising from the experience of service use are constantly being raised. The purpose of this study was to investigate empirically the effects of individual trust in AI and online privacy concerns on the continued use of AI-based voice assistants, specifically the impact of their interaction. In this study, question items were constructed based on previous studies, with an online survey conducted among 405 respondents. The effect of the user's trust in AI and privacy concerns on the adoption and continuous use intention of AI-based voice assistant services was analyzed using the Heckman selection model. As the main findings of the study, first, AI-based voice assistant service usage behavior was positively influenced by factors that promote technology acceptance, such as perceived usefulness, perceived ease of use, and social influence. Second, trust in AI had no statistically significant effect on AI-based voice assistant service usage behavior but had a positive effect on continuous use intention. Third, the privacy concern level was confirmed to have the effect of suppressing continuous use intention through interaction with trust in AI. These research results suggest the need to strengthen user experience through user opinion collection and action to improve trust in technology and alleviate users' concerns about privacy as governance for realizing digital government. When introducing artificial intelligence-based policy services, it is necessary to disclose transparently the scope of application of artificial intelligence technology through a public deliberation process, and the development of a system that can track and evaluate privacy issues ex-post and an algorithm that considers privacy protection is required.

Research on Factors Affecting Smartphone App Market Selection: App Market Platform Provider's Perspective (스마트폰 앱 마켓 선택에 영향을 미치는 요인에 관한 연구: 앱 마켓 플랫폼 사업자 관점으로)

  • Lee, Ho;Kim, Jae Sung;Kim, Kyung Kyu;Lee, Youngin
    • Journal of the Korea Knowledge Information Technology Society
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    • v.13 no.1
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    • pp.11-23
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    • 2018
  • This paper empirically investigates the factors that influence the consumer choice of an app market based on the rational choice theory. The app market is the only channel where a consumer can buy smartphone apps, which give various functional convenience and are considered to be a major contributor to the proliferation of smartphones. Analyses of 281 questionnaires show that usability and structural guarantees as benefit factors significantly influence the app market choice. From the cost perspectives, both monetary and non-monetary conversion costs are found to significantly influence the app market choice. On the other hand, customer trust, information quality, and market image were found to have no significant effect on app market selection. In particular, Korean app market platform providers (KT, LG U +) seem to be superior in terms of structural guarantees, such as customer center operation and damage compensation regulations, compared to overseas app market platform operators (Google). However, in the case of the Google App Market, it is pre-installed on all Android phones, so it is not inconvenient to install additional apps to use other app market. This is disadvantageous to domestic app market platform operators, and it is necessary to establish a policy solution point. In terms of operator costs, both monetary and non-monetary conversion costs have a significant impact on app market choice. In particular, non-monetary conversion costs have a negative impact on Korean app market platform operators. It can be explained that the service expectation level of the domestic app market is low and it is recognized that the time cost factor such as membership is large for new users to use. It seems to be necessary to improve the domestic app market business. Meanwhile, extant research on smartphone apps focuses on the purchase of apps themselves, but not on the selection of the app market itself. In order to fill in this gap, this study focuses on the determinants of app market selection, including the characteristics of an app market and the switching costs.

A Study on Establishment of Safety Training Center Based on Virtual Reality and Augmented Reality Technology for Military Safety and Suicide Accident Prevention (가상현실(VR/AR) 기술 기반으로 군 안전 및 자살사고 예방을 위한 안전체험훈련장 구축 방안에 관한 연구)

  • Choi, Sung-oh;Min, Yong-sik;Kim, Sung-Il;Ghoi, Jong-geun
    • Journal of Internet Computing and Services
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    • v.21 no.2
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    • pp.139-148
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    • 2020
  • Due to change in circumstances in the 2000s such as severe birthrate decline and shortened military service period, the armed forces of the Republic of Korea is currently turning to technologies and equipments from manpower, developing it to become high-tech, high-speed, and complex, resulting in an environment in which a single mistake could cause a mass mortality crisis.It is also evident that, considering aspects such as safety training curriculums and achievements of advanced countries and private education, hands-on training is a must in preventing suicides and accidents in the military, and establishing safety training centers is crucial for systematic and effective hands-on training.Soldiers who are joining the army as of now have experienced the Internet ever since they were born and easily use both virtual and augmented reality, and the current level of science and technology has developed to the point where most of the public safety experience centers are able to be replaced by virtual and augmented reality (VR/AR). Therefore, considering the aspects such as installation space, construction costs, maintenance costs, user characteristics, and education effects, other than for those trainings where real models and objects are more effective such as first aid training, it is with a strong recommendation that establishing military safety training facilities with VR/AR (Virtual and augmented reality) is a must in the coming future. We have derived the need for hands-on training by considering the development of virtual and augmented reality (VR/AR), analysis of operation status of the public safety experience centers, characteristics of military units, installation and maintenance costs, and proposed plan to establish safety training centers where effective training performance can be achieved at a lower cost than the public safety experience center. In addition, we suggested the scale of the required safety training center and the composition of the experience rooms considering the number of trainees and the environment of each military units. Given this analysis it will contribute to the prevention of military safety and suicide by building a safety training center in the future.

The Extended Site Assessment Procedure Based on Knowledge of Biodegradability to Evaluate the Applicability of Intrinsic Remediation (자연내재복원기술(Intrinsic Remediation)적용을 위한 오염지역 평가과정 개발)

  • ;Robert M. Cowan
    • Journal of Korea Soil Environment Society
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    • v.2 no.3
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    • pp.3-21
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    • 1997
  • The remediation of contamiated sites using currently available remediation technologies requires long term treatment and huge costs, and it is uncertain to achieve the remediation goal to drop contamination level to either back-ground or health-based standards by using such technologies. Intrinsic remediation technology is the remediation technology that relies on the mechanisms of natural attenuation for the containment and elimination of contaminants in subsurface environments. Initial costs for the intrinsic remediation may be higher than conventional treatment technologies because the most comprehensive site assessment for intrinsic remediation is required. Total remediation cost, however may be the lowest among the presently employed technologies. The applicability of intrinsic remediation in the contaminated sites should be theroughly investigated to achieve the remedial goal of the technology. This paper provides the frame of the extended site assessment procedure based on knowledge of biodegradability to evaluate the applicability of intrinsic remediation. This site assessment procedure is composed of 5 steps such as preliminary site screening, assessment of the current knowledge of biodegradability, selecting the appropriate approach, analyzing the contaminant fate and transport and planning the monitoring schedule. In the step 1, followings are to be decided 1) whether to go on the the detailed assessment or not based on the rules of thumb concerning the biodegradability of organic compounds, 2) which protocol document is selected to follow for detailed site assessment according to the site characteristics, contaminants and the relative distance between the contamination and potential receptors. In the step 2, the database for biodegradability are searched and evaluated. In the step 3, the appropriate biodegradability pathways for the contaminated site is selected. In the step 4, the fate and transport of the contaminants at the site are analyzed through modeling. In the step 5, the monitoring schedule is planned according to the result of the modeling. Through this procedure, users may able to have the rational and systematic informations for the application of intrinsic remediation. Also the collected data and informations can be used as the basic to re-select the other remediation technology if it reaches a conclusion not to applicate intrinsic remediation technology at the site from the site assessment procedure.

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Hypertension Management Status in Rural Hypertensives (농촌지역(農村地域) 고혈압환자(高血壓患者)의 고혈압(高血壓) 관리행태(管理行態))

  • Kim, Hyun-Sook;Kam, Sin;Kim, Jong-Yeon;Park, Ki-Soo;Lee, Kyeong-Soo
    • Journal of agricultural medicine and community health
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    • v.28 no.1
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    • pp.93-106
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    • 2003
  • Objectives: This study was conducted to investigate the treatment status and its related factors of the rural hypertensives. Methods: A questionnaire survey was performed to 618 rural hypertensives during September, 2002. Results: The proportion of those who were compliant to the antihypertensive medication was 68.9%. The compliance rate to the antihypertensive medication was significantly related with sex and economic status(p<0.05). That is, if they were female, higher economic level, the regular antihypertensive medication rate was higher. The regular antihypertensive medication rate was higher when they had higher knowledge for hypertension, higher severity for hypertension of him or her(p<0.01). And the compliance rate to the antihypertensive medication was significantly related with hypertensives' own explanatory model for hypertension(p<0.01). The rate of drug use except antihypertensives was 12.5%. The rate of drug use except antihypertensives was higher when they experienced side effects of antihypertensive drug and when they had irregular medication for antihypertensive drug(p<0.01). The rate of medical equipment use was 18.9%. The utilization rate of medical equipment such as jade mat, germanium material was significantly related with age, experience of side effects of antihypertensive drug, medication status for antihypertensive drug(p<0.05). The rate of folk therapy use was 16.2%. The rate of folk therapy use was higher when they had no family, when they had knowledge about hypertension on the average, when they had hypertension over 10 years(p<0.05), and when they experienced side effects of antihypertensive drug and when they had irregular medication for antihypertensive drug(p<0.01). The rates of drug use except antihypertensives, medical equipment use, and folk therapy were significantly related with hypertensives' own explanatory model for hypertension(p<0.05). Conclusions: On consideration of above findings, it would be essential to provide knowledge about hypertension and its treatment, and severity of hypertension complications through health education.

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Study on 3D Printer Suitable for Character Merchandise Production Training (캐릭터 상품 제작 교육에 적합한 3D프린터 연구)

  • Kwon, Dong-Hyun
    • Cartoon and Animation Studies
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    • s.41
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    • pp.455-486
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    • 2015
  • The 3D printing technology, which started from the patent registration in 1986, was a technology that did not attract attention other than from some companies, due to the lack of awareness at the time. However, today, as expiring patents are appearing after the passage of 20 years, the price of 3D printers have decreased to the level of allowing purchase by individuals and the technology is attracting attention from industries, in addition to the general public, such as by naturally accepting 3D and to share 3D data, based on the generalization of online information exchange and improvement of computer performance. The production capability of 3D printers, which is based on digital data enabling digital transmission and revision and supplementation or production manufacturing not requiring molding, may provide a groundbreaking change to the process of manufacturing, and may attain the same effect in the character merchandise sector. Using a 3D printer is becoming a necessity in various figure merchandise productions which are in the forefront of the kidult culture that is recently gaining attention, and when predicting the demand by the industrial sites related to such character merchandise and when considering the more inexpensive price due to the expiration of patents and sharing of technology, expanding opportunities and sectors of employment and cultivating manpower that are able to engage in further creative work seems as a must, by introducing education courses cultivating manpower that can utilize 3D printers at the education field. However, there are limits in the information that can be obtained when seeking to introduce 3D printers in school education. Because the press or information media only mentions general information, such as the growth of the industrial size or prosperous future value of 3D printers, the research level of the academic world also remains at the level of organizing contents in an introductory level, such as by analyzing data on industrial size, analyzing the applicable scope in the industry, or introducing the printing technology. Such lack of information gives rise to problems at the education site. There would be no choice but to incur temporal and opportunity expenses, since the technology would only be able to be used after going through trials and errors, by first introducing the technology without examining the actual information, such as through comparing the strengths and weaknesses. In particular, if an expensive equipment introduced does not suit the features of school education, the loss costs would be significant. This research targeted general users without a technology-related basis, instead of specialists. By comparing the strengths and weaknesses and analyzing the problems and matters requiring notice upon use, pursuant to the representative technologies, instead of merely introducing the 3D printer technology as had been done previously, this research sought to explain the types of features that a 3D printer should have, in particular, when required in education relating to the development of figure merchandise as an optional cultural contents at cartoon-related departments, and sought to provide information that can be of practical help when seeking to provide education using 3D printers in the future. In the main body, the technologies were explained by making a classification based on a new perspective, such as the buttress method, types of materials, two-dimensional printing method, and three-dimensional printing method. The reason for selecting such different classification method was to easily allow mutual comparison of the practical problems upon use. In conclusion, the most suitable 3D printer was selected as the printer in the FDM method, which is comparatively cheap and requires low repair and maintenance cost and low materials expenses, although rather insufficient in the quality of outputs, and a recommendation was made, in addition, to select an entity that is supportive in providing technical support.

Development of a Stock Trading System Using M & W Wave Patterns and Genetic Algorithms (M&W 파동 패턴과 유전자 알고리즘을 이용한 주식 매매 시스템 개발)

  • Yang, Hoonseok;Kim, Sunwoong;Choi, Heung Sik
    • Journal of Intelligence and Information Systems
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    • v.25 no.1
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    • pp.63-83
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    • 2019
  • Investors prefer to look for trading points based on the graph shown in the chart rather than complex analysis, such as corporate intrinsic value analysis and technical auxiliary index analysis. However, the pattern analysis technique is difficult and computerized less than the needs of users. In recent years, there have been many cases of studying stock price patterns using various machine learning techniques including neural networks in the field of artificial intelligence(AI). In particular, the development of IT technology has made it easier to analyze a huge number of chart data to find patterns that can predict stock prices. Although short-term forecasting power of prices has increased in terms of performance so far, long-term forecasting power is limited and is used in short-term trading rather than long-term investment. Other studies have focused on mechanically and accurately identifying patterns that were not recognized by past technology, but it can be vulnerable in practical areas because it is a separate matter whether the patterns found are suitable for trading. When they find a meaningful pattern, they find a point that matches the pattern. They then measure their performance after n days, assuming that they have bought at that point in time. Since this approach is to calculate virtual revenues, there can be many disparities with reality. The existing research method tries to find a pattern with stock price prediction power, but this study proposes to define the patterns first and to trade when the pattern with high success probability appears. The M & W wave pattern published by Merrill(1980) is simple because we can distinguish it by five turning points. Despite the report that some patterns have price predictability, there were no performance reports used in the actual market. The simplicity of a pattern consisting of five turning points has the advantage of reducing the cost of increasing pattern recognition accuracy. In this study, 16 patterns of up conversion and 16 patterns of down conversion are reclassified into ten groups so that they can be easily implemented by the system. Only one pattern with high success rate per group is selected for trading. Patterns that had a high probability of success in the past are likely to succeed in the future. So we trade when such a pattern occurs. It is a real situation because it is measured assuming that both the buy and sell have been executed. We tested three ways to calculate the turning point. The first method, the minimum change rate zig-zag method, removes price movements below a certain percentage and calculates the vertex. In the second method, high-low line zig-zag, the high price that meets the n-day high price line is calculated at the peak price, and the low price that meets the n-day low price line is calculated at the valley price. In the third method, the swing wave method, the high price in the center higher than n high prices on the left and right is calculated as the peak price. If the central low price is lower than the n low price on the left and right, it is calculated as valley price. The swing wave method was superior to the other methods in the test results. It is interpreted that the transaction after checking the completion of the pattern is more effective than the transaction in the unfinished state of the pattern. Genetic algorithms(GA) were the most suitable solution, although it was virtually impossible to find patterns with high success rates because the number of cases was too large in this simulation. We also performed the simulation using the Walk-forward Analysis(WFA) method, which tests the test section and the application section separately. So we were able to respond appropriately to market changes. In this study, we optimize the stock portfolio because there is a risk of over-optimized if we implement the variable optimality for each individual stock. Therefore, we selected the number of constituent stocks as 20 to increase the effect of diversified investment while avoiding optimization. We tested the KOSPI market by dividing it into six categories. In the results, the portfolio of small cap stock was the most successful and the high vol stock portfolio was the second best. This shows that patterns need to have some price volatility in order for patterns to be shaped, but volatility is not the best.

Development of Drawing & Specification Management System Using 3D Object-based Product Model (3차원 객체기반 모델을 이용한 설계도면 및 시방서관리 시스템 구축)

  • Kim Hyun-nam;Wang Il-kook;Chin Sang-yoon
    • Korean Journal of Construction Engineering and Management
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    • v.1 no.3 s.3
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    • pp.124-134
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    • 2000
  • In construction projects, the design information, which should contain accurate product information in a systematic way, needs to be applicable through the life-cycle of projects. However, paper-based 2D drawings and relevant documents has difficulties in communicating and sharing the owner's and architect's intention and requirement effectively and building a corporate knowledge base through on-going projects due to Tack of interoperability between specific task or function-oriented software and handling massive information. Meanwhile, computer and information technologies are being developed so rapidly that the practitioners are even hard to adapt them into the industry efficiently. 3D modeling capabilities in CAD systems are enormously developed and enables users to associate 3D models with other relevant information. However, this still requires a great deal of efforts and costs to have all the design information represented in CAD system, and the sophisticated system is difficult to manage. This research focuses on the transition period from 2D-based design Information management to 3D-based, which means co-existence of 2D and 3D-based management. This research proposes a model of a compound system of 2D and 3D-based CAD system which presents the general design information using 3D model integrating with 2D CAD drawings for detailed design information. This research developed an integrated information management system for design and specification by associating 2D drawings and 3D models, where 2D drawings represents detailed design and parts that are hard to express in 3D objects. To do this, related management processes was analyzed to build an information model which in turn became the basis of the integrated information management system.

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A Study on the Real Condition and the Improvement Directions for the Protection of Industrial Technology (산업기술 보호 관리실태 및 발전방안에 관한 연구)

  • Chung, Tae-Hwang;Chang, Hang-Bae
    • Korean Security Journal
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    • no.24
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    • pp.147-170
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    • 2010
  • This study is to present a improvement directions for the protection of industrial key technology. For the purpose of the study, the survey was carried out on the administrative security activity of 68 enterprises including Large companies, small-midium companies and public corporations. survey result on the 10 items of security policy, 10 items of personal management and 7 items of the assets management are as follows; First, stable foundation for the efficient implement of security policy is needed. Carrying a security policy into practice and continuous upgrade should be fulfilled with drawing-up of the policy. Also for the vitalization of security activity, arrangement of security organization and security manager are needed with mutual assistance in the company. Periodic security inspection should be practiced for the improvement of security level and security understanding. Second, the increase of investment for security job is needed for security invigoration. Securing cooperation channel with professional security facility such as National Intelligence Service, Korea internet & security agency, Information security consulting company, security research institute is needed, also security outsourcing could be considered as the method of above investment. Especially small-midium company is very vulnerable compared with Large company and public corporation in security management, so increase of government's budget for security support system is necessary. Third, human resource management is important, because the main cause of leak of confidential information is person. Regular education rate for new employee and staff members is relatively high, but the vitalization of security oath for staff members and the third party who access to key technology is necessary. Also access right to key information should be changed whenever access right changes. Reinforcement of management of resigned person such as security oath, the elimination of access right to key information and the deletion of account. is needed. Forth, the control and management of important asset including patent and design should be tightened. Classification of importance of asset and periodic inspection are necessary with the effects evaluation of leak of asset.

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